关键词: 石油, 二氧化碳捕集, 经济, 制氢, 催化裂化, 原位富集

Abstract:

The CO₂ emissions from the Fluidized Catalytic Cracking (FCC) regenerator are one of the major process emissions in the petrochemical industry, and it is a key focus for refining companies to achieve green and low-carbon transformation. The in-situ CO₂ enrichment process utilizes flue gas circulation to enrich CO₂ within the FCC regenerator, achieving low-cost and efficient CO₂ capture. However, the additional requirement for pure O₂ increases the energy consumption costs of the process. To further reduce CO₂ capture costs, this paper proposes a coupled process of FCC regenerator CO₂ in-situ enrichment with green hydrogen production. Based on material balance and process simulation methods, a process redesign for an 800,000 ton/year FCC unit at a refinery matches a corresponding-scale electrolyzer to supply oxygen for the CO₂ in-situ enrichment process. The hydrogen by-product from water electrolysis replaces the refinery's natural gas-based hydrogen production unit of similar scale for downstream hydrogenation processes. Further economic analysis is conducted on the new coupled process based on industrial project construction experience and process simulation results, and it is compared with the conventional FCC regeneration and natural gas hydrogen production process combination with amine absorption CO₂ capture. The results show that the new coupled process CO₂ emission reduction cost is 109.9 CNY/tCO₂, 40.5% lower than the conventional process combination, confirming the economic feasibility of the new coupled process. Additionally, the impact of grid electricity prices, natural gas prices, carbon emission quota prices, and carbon utilization revenues on the economics of the conventional and new coupled processes is examined. The results indicate that the new coupled process is most sensitive to grid electricity prices, and its operating costs can be further reduced in the future by increasing the proportion of renewable energy supply. Meanwhile, the economics of the new coupled process are less affected by carbon utilization revenues, showing better resilience to CO₂ market price fluctuations compared to the conventional process.

Key words: petroleum, CO₂ capture, economics, hydrogen production, catalytic cracking, in-situ enrichment